Electrical lights have been around for well over 100 years. During that time, many variations and improvements in the technologies utilized to produce light have occurred. One of the most recent developments has been the widespread adoption of Light Emitting Diode (LED) lighting systems as a replacement for older incandescent and fluorescent systems.
In the last twenty years, rapid commercialization of LED technologies has occurred. LED lighting systems can be found in everything from hand-held flashlights to standard floor and desk lamps. In fact, the more powerful LEDs of recent manufacture are even being utilized in large-scale outdoor lighting projects.
Nevertheless, while LED lights have made impressive inroads in many areas of the lighting industry, current LED systems still have a few problems and limitations. One such limitation is the general lack of LED controller systems that provide varying intensity outputs for LED lighting systems. A variety of multi-step systems are available, but the resulting lighting effect is similar to a standard three-way incandescent bulb in that three predefined levels of brightness are apparent rather than a smooth increasing and decreasing of the light output levels.
Another technology that is often utilized in LED systems is called a Pulse Width Modulator (PWM). PWMs are used to control the light output of LEDs. A PWM acts by providing segmented pulses of voltage to a LED, causing a flashing or pulsing effect in the light output of the LED. The pulsing effect causes the human eye to perceive an erratic flashing effect when a PWM is used to dim or brighten LED lights. Thus, a need exists for a LED controller and lighting system that can smoothly increase and decrease LED light output intensities without utilizing apparent brightness steps/levels or causing a pulsing of the LED.
As LED lighting systems have grown and evolved so too have passive solar lighting solutions, i.e., skylights. One common embodiment has seen a recent surge in installations because of its flexibility: the tube skylight. The traditional skylight is a window-like device that is placed in the roof of a building and allows sunlight to shine in from above. If a building has an attic area beneath the roof, it is difficult to utilize a traditional skylight since the attic blocks the path of the sunlight into the interior of the building. In such a situation, a serviceable alternative is the tube skylight. Tube skylights utilize a cylindrically shaped pipe, tube or other similar structure to direct and funnel the outside light from the skylight through an attic and into the ceiling of a room in the interior of a building. The inside of the tube-structure is reflective, allowing the structure to be bent, angled, and turned without significantly reducing the amount of outside light transmitted to the room below.
Although the tube skylight has significant advantages over the traditional skylight, both suffer from the same inherent deficiency: at night (or on cloudy days), there is little outside light for a skylight to transmit into a building. In order to overcome this shortcoming, lighting companies have begun to offer incandescent add-on lights that can be attached to skylights. However, installations of such lights usually require the services of an electrician since standard household alternating current is used to power the lights. Furthermore, the additional wiring that is required can add considerable expense to the lighting project. Additional problems with the traditional incandescent approach include: relatively low efficiency, high heat output per lumen of light, large size, difficulty installing and changing bulbs, etc. Therefore, there is a need for a skylight lighting add-on that is efficient, comparatively cool, and relatively inexpensive and simple to install.